Science Forum

Science Forum

  1. Subscribersonhouse
    Fast and Curious
    slatington, pa, usa
    Joined
    28 Dec '04
    Moves
    52874
    09 Jun '19 18:15
    For fuel cells, much lighter that batteries, more energy stored, for drones and such and off grid power.

    https://phys.org/news/2019-06-core-shell-catalyst-ethanol-fuel-cells.html
  2. Joined
    06 Mar '12
    Moves
    625
    10 Jun '19 11:2411 edits
    I am making a prediction; It won't be ethanol that will be the biofuel of the future but 2-octanol
    ( https://en.wikipedia.org/wiki/2-Octanol )
    and this is because it will be perfect for future fuel cells and fuel cells will replace the combustion engines.
    Why 2-octanol and not, say, ethanol etc?

    1, it is one of the least toxic alcohols, even less toxic than 1-octanol and way less toxic than ethanol. It is so low toxic that it is said to be "none-toxic".

    2, it has a specific density (which is energy density in terms of per mass rather than per volume) a bit higher than that of ethanol although still lower than petrol.
    Specific energy of ethanol is about 29.6 MJ/kg.
    Specific energy of 2-octanol is about 40.4 MJ/kg.
    Specific energy of petrol is about 47 MJ/kg.
    Specific energy of 2-octanol more than good enough!

    3, it has sufficient low solubility in water that, unlike with ethanol, you don't have to use up energy in separating in from water from its production.
    At the same time it has sufficient high solubility in water to aid in its use in fuel cells where it would help if the catalysts work in the presence of water (which will be a byproduct of oxidation anyway).
    In other words, its solubility in water is not too high or not too low but just right.
    Solubility of ethonal; miscible.
    Solubility of 2-octanol; about 1.1g/l
    Solubility of petrol; near-enough none.

    4, It has a relatively high flash point (71C, which is much higher than that of ethanol or petrol) which is great for fire safety.
    Flash point of ethanol is about 14C.
    Flash point of 2-octanol is about 71C.
    Flash point of petrol is less than -40C.

    I have studied many chemical compounds for biofuels and have concluded that, at least if its for fuel cells, 2-octanol is overall the best one for general purposes because of the above.
    A good fuel cell for 2-octanol has yet to be invented but its just a matter of when, not if.
  3. Subscribersonhouse
    Fast and Curious
    slatington, pa, usa
    Joined
    28 Dec '04
    Moves
    52874
    10 Jun '19 14:30
    @humy said
    I am making a prediction; It won't be ethanol that will be the biofuel of the future but 2-octanol
    ( https://en.wikipedia.org/wiki/2-Octanol )
    and this is because it will be perfect for future fuel cells and fuel cells will replace the combustion engines.
    Why 2-octanol and not, say, ethanol etc?

    1, it is one of the least toxic alcohols, even less toxic than 1-octanol and ...[text shortened]... above.
    A good fuel cell for 2-octanol has yet to be invented but its just a matter of when, not if.
    Then the question is how is 2 oct made? Is it made from ethanol? I know next to nothing about organic chemistry. The specs you put in clearly show it's superiority but the main point is can it be made in industrial levels and can the technology of the ethanol catalyst just invented work for 2 oct? That is a question we cannot answer ATT because their technology is so new they haven't optimized it yet, and have yet to even make a real product, it is still a lab result but very promising.
    Their point was even as little energy density ethanol has compared to others, it is still a lot higher than Lithium ion batteries which is the best we can do for drones ATT, a 20 minute flight time is all they can do with that technology so anything that can improve on that is gravy.
    Another issue is any kind of fuel cell used with electric vehicles are going to be more efficient than petrol engines because of the heat losses and friction of piston engines. Electric motors just take electrical energy and convert it to motion at 90% efficiency and of course you lose some of that in the drive train unless you put the motors in the tires themselves but the bottom line is electric vehicles are much more efficient in the use of energy available so even if a vehicle uses pure ethanol with this new tech the range will be better than any battery system and can only get a lot better if we can manage to do the same with 2 oct stuff.
    This catalyst is a great step along the path to get us off oil for transportation.

    I see vehicles in the future with that kind of tech combined with solar cells on the cars and there was one report about work being done on solar cell paint where the whole car is generating power, parked on a sunny day and 8 hours later the car has a full charge just from that.

    Of course 100 years from now the culture of transport may be totally transformed to some kind of universal public transport or some such where cars are not even legal any more but time will tell.
  4. Joined
    06 Mar '12
    Moves
    625
    10 Jun '19 14:454 edits
    @sonhouse said
    Then the question is how is 2 oct made? Is it made from ethanol?
    Its currently normally made from castor oil but, with suitable catalysts or artificial enzymes, it could in theory be made from vertually any organic chemical including ethanol. One of my ideas for the far future is that it could be made from artificial digestion of organic waste as the raw material, such as grass clippings and garden waste and human sewage etc (with fertilizer made as a valuable byproduct). Another idea is to fix CO2 straight out of the atmosphere using energy from renewables and then using that + H2O + artificial enzymes to make 2-oct. I have worked out many of the details of a very complex scheme to do exactly that although I am afraid it couldn't happen until something like ~300 years in the future because this would require certain massive new advances in technology which we aren't even close to achieving any time soon; UNLESS that is my life-long plan to make a huge breakthrough in AI actually works and then that AI would work out how to do all that and much more within in something like only ~1 year!
  5. Subscribersonhouse
    Fast and Curious
    slatington, pa, usa
    Joined
    28 Dec '04
    Moves
    52874
    10 Jun '19 16:52
    @humy said
    Its currently normally made from castor oil but, with suitable catalysts or artificial enzymes, it could in theory be made from vertually any organic chemical including ethanol. One of my ideas for the far future is that it could be made from artificial digestion of organic waste as the raw material, such as grass clippings and garden waste and human sewage etc (with fertilizer ...[text shortened]... then that AI would work out how to do all that and much more within in something like only ~1 year!
    AI is already being used in several fields with real results so you better hurry up, you will be beaten to the game.
Back to Top